Yarn delivery apparatus having two delivery rollers

ABSTRACT

A yarn delivery apparatus is provided having two delivery rollers of which one of the delivery rollers is resiliently biased against the other delivery roller and one of the two delivery rollers is floatingly mounted such that it is disposed for a selected one of a swivel and a swinging movement relative to the other delivery roller. The yarn delivery apparatus being characterized in that the floatingly mounted delivery roller is configured as a rotationally symmetrical hollow body whose inner wall is supported on a ball-shaped support body which is secured to an axial shaft in a manner such that the position of the floatingly mounted delivery roller can be changed only within a plane defined by the axes of the two delivery rollers.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a yarn delivery apparatus having two delivery rollers of which one roller is resiliently biased against the other roller, whereby one of the two rollers is floatingly mounted such that it is capable of swivel movement or pivot movement relative to the other roller.

[0002] Yarn delivery apparatus such as those of the type described, for example, in DE-OS 26 58 995, have at least one of their two rollers rotatably driven by an external drive while the other roller, if it is not externally rotatably driven, is set into rotation by the action of the yarn being drawn through the nip formed between the two rollers. Both rollers are arranged parallel to one another, whereby one of the two rollers typically is movable away from the other roller in either a translational or swivel movement to permit placement of the yarn into the yarn delivery apparatus and the swung away roller is then movable toward the other roller after placement of the yarn. With conventional yarn delivery apparatus, the distance between the two rollers during operation of the yarn delivery apparatus is principally determined by the thickness of the yarn moving therepast, whereby this distance ideally should remain constant over the entire axial length of the roller. In order to improve the relative parallel orientation of the roller axes to one another, the yarn delivery apparatus described in DE-OS 26 58 995 has one of its rollers disposed on a spring biased swivel arm which is configured as a self-centering pivot arm pivoting about a pivot point. It is understood that an equalization of the clamping pressure applied to the yarn as it is moved between the rollers, and thus a uniform yarn movement, will be achieved by an improvement of the relative parallel orientation of the rollers.

[0003] The problem which the present invention addresses is one that arises if a yarn delivery apparatus is to simultaneously feed to a machine two yarns having differing thickness or denier such as, for example, yarns for the production of effect yarns, as in this circumstance the roller nip is set by the thickness of the relatively thicker yarn and the relatively thinner yarn thus does not undergo the desired treatment thereof by the rollers.

[0004] In the situation, as well, in which the yarn delivery apparatus is to feed two or more yarns of the same thickness, there can arise a circumstance if, for example, one of the fed yarns has a transitory yarn thickening, wherein the distance between the two rollers increases in correspondence with the yarn thickening as it passes between the rollers with the result that the other yarn that does not have the yarn thickening is no longer in contact with the outer surface of the two rollers. In this manner, a slippage of the yarn can occur with a consequential non-uniform feed of this second yarn or yarn section. If, on the other hand, one of the two yarns has a transitory yarn reduced cross section or thinning, this one yarn or yarn section having the yarn thinning will no longer move between the rollers in a non-slip manner for the reason that the distance between the two rollers cannot change—that is, the distance cannot correspondingly decrease—because this distance is set by the thickness of the other yarn or yarn section.

[0005] The yarn delivery apparatus described in DE-OS 26 58 995, which has, for supporting one of the rollers, a swivel arm configured as a self-centering pivot arm pivoting about a pivot point, is capable of solving the above-noted problem of simultaneous feeding of two yarns if one attempts to improve the relative parallel orientation of the axes of the two rollers to one another.

[0006] The disadvantage of the conventional yarn delivery apparatus lies in the fact that a relatively large system is pivotally supported on a pivot point—namely, the swivel arm supporting one of the rollers which is adjacent this roller and which is, moreover, under a spring loading.

SUMMARY OF THE INVENTION

[0007] The present invention provides a solution to the challenge of providing a yarn delivery apparatus for simultaneous feed of two yarns which is simpler than conventional yarn delivery apparatus and with which a uniform non-slip feed of both yarns is ensured independent of differing thickness or denier of the two yarns or the occurrence of yarn thickening or thinning.

[0008] The solution provided by the present invention is a yarn delivery apparatus whose floatingly mounted roller is configured as a rotationally symmetrical hollow body the inner wall of which is supported on a ball-shaped support body secured to an axial shaft in a manner such that the position of the floatingly mounted roller can only be varied within the plane defined by the axes of the two rollers.

[0009] As a result of the floating mounting solely of the one roller, this one roller is capable, without regard to an overly high inertia, of assuming an angled position in the event of a yarn thickening or thinning of one of the two yarns moving between the two rollers so that the compressive force acting on both of the two yarn sections moving through the roller nip remains constant in order that both yarns are fed in a non-slip manner, thus a uniform manner, through the yarn delivery apparatus.

[0010] In particular, the support body which is mounted on a stationary axis preferably has a spherical shape.

[0011] In order to prevent a deviating movement of the floatingly mounted delivery roller in a direction lying outside of the plane defined by the axes of the two rollers, the yarn delivery apparatus, in accordance with one preferred embodiment, comprises stop members pressed against the floatingly mounted roller which are oriented, on the one hand, parallel to the plane defined by the axes of the two rollers and, on the other hand, perpendicular to the roller nip of the yarn delivery apparatus.

[0012] The yarn delivery apparatus of the present invention can also be deployed with particular advantage in a system as described in EP 0 701 014 B1 (U.S. Pat. No. 5,626,011) if, during a spin yarn joining step in an integrated open end spinning and doubling twist yarn process with a drawing out of the twist yarn through the spindle hollow axle shaft of the doubling twist spindle, there is a simultaneous feeding of both spin joining yarns into the open end spinning rotors.

BRIEF DESCRIPTION OF THE DRAWING

[0013] This object, and other objects and advantages of the present invention, will appear more clearly from the following specification in conjunction with the accompanying schematic drawings, in which:

[0014]FIG. 1 is a perspective view of a first embodiment of the yarn delivery apparatus of the present invention; and

[0015]FIG. 2 is a perspective view of a second embodiment of the yarn delivery apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] As seen in FIG. 1, the yarn delivery apparatus is comprised of two delivery rollers 1 and 2 of which the delivery roller 1 is mounted on a spring loaded swivel arm 10 so that the delivery roller can be swiveled away from the delivery roller 2 for placement of the yarns A and B on the delivery rollers and can then be disposed again against the delivery roller 2 after the placement of the yarns. On the swivel arm 10 is secured, for example, one end of a pull spring 11 while the other end of the pull spring 11 is secured to a stationary component (not shown) of, for example, the yarn delivery apparatus or the textile machine frame.

[0017] As seen in FIG. 2, the delivery roller 2 is configured as a hollow body whose inner wall is supported on a ball-shaped support body 12 which is preferably spherically shaped and is mounted on a stationary axial shaft 3. Stop members 13, 14 are applied against the outer circumferential surface of the delivery roller 2 or against the projections 2.1 of the delivery roller 2 which are concentric to the outer circumferential surface of the delivery roller, the stop members being oriented, on the one hand, parallel to the plane defined by the axes of the two rollers and, on the other hand, perpendicular to the roller nip of the delivery rollers. In this manner, it is ensured that the delivery roller 2 can only change position about an axis in a plane which is defined by the axes of the two delivery rollers while the stop members 13, 14, which press against the top side of the delivery roller 2, prevent a swiveling or tilting of the delivery roller 2 about a horizontal axis lying in a plane which is tangential to the cylindrical sleeve surfaces of the two delivery rollers 1, 2 in the area of the roller nip where these sleeve surfaces contact one another.

[0018] If one of the two yarns or yarn sections A and B moving through the delivery rollers, such as, for example, the yarn section A, comprises a yarn thickening or thinning, the delivery roller 2 is disposed to make a deviating movement, in correspondence with the yarn thickening or thinning, such that the delivery roller 2 assumes an angled disposition relative to the delivery roller 1 in correspondence with the yarn thickening or thinning. The roller nip is consequently larger or smaller in the area of the yarn section A while, in the area of the yarn section B, the roller nip maintains its original size corresponding to the yarn thickness of the yarn section B. In this manner, it is ensured that the compressive force exerted by the delivery rollers 1 and 2 on the two yarn sections A and B remains constant, whereby a uniform and slip free feed of both yarn sections A and B through the yarn delivery apparatus is ensured.

[0019] One of the two delivery rollers—preferably, the delivery roller 1—can, as seen in FIG. 1, be rotatably driven by a motor 12 which is supported, as an example, on the swivel arm 10. Driving rotation of both delivery rollers can also be accomplished, as shown in FIG. 2, by exerting a pulling force on one of the two yarn sections A or B, whereby both delivery rollers 1 and 2 are correspondingly rotatably driven and the other respective yarn section is correspondingly mutually fed along with the pulled yarn section.

[0020] The specification incorporates by reference the disclosure of German priority document 100 21 159.3-26 of Apr. 29, 2000.

[0021] The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims. 

What I claim is:
 1. A yarn delivery apparatus comprising: two delivery rollers, one of the delivery rollers being resiliently biased against the other delivery roller and one of the two delivery rollers being floatingly mounted such that it is disposed for a selected one of a swivel and a swinging movement relative to the other delivery roller, the floatingly mounted delivery roller being configured as a rotationally symmetrical hollow body whose inner wall is supported on a ball-shaped support body which is secured to an axial shaft in a manner such that the position of the floatingly mounted delivery roller can be changed only within a plane defined by the axes of the two delivery rollers.
 2. A yarn delivery apparatus according to claim 1 , wherein the axial shaft is stationary.
 3. A yarn delivery apparatus according to claim 1 , wherein the ball-shaped support body has a spherical shape.
 4. A yarn delivery apparatus according to claim 1 , and further comprising stop members oriented, on the one hand, parallel to the plane defined by the axes of the two rollers and, on the other hand, perpendicular to the roller nip of the delivery rollers.
 5. A yarn delivery apparatus according to claim 1 , wherein the non-floatingly mounted delivery roller is swivelable against the other delivery roller.
 6. A yarn delivery apparatus according to claim 5 , wherein the non-floatingly mounted delivery roller is rotatably mounted on a swivel arm.
 7. A yarn delivery apparatus according to claim 6 , wherein a spring is connected to the swivel arm.
 8. A yarn delivery apparatus according to claim 6 , wherein the swivel arm supports thereon a motor for driving rotation of the delivery roller. 